Atherosclerosis and Coronary Artery Disease

Medically Reviewed by James Beckerman, MD, FACC on May 26, 2024
3 min read

Atherosclerosis -- sometimes called hardening of the arteries -- can slowly narrow the arteries throughout your body.

When atherosclerosis affects arteries that carry blood to the heart muscle, it’s called coronary artery disease, or CAD. That’s the No. 1 killer of Americans. Most of those deaths are from heart attacks caused by blood clots.

Atherosclerosis can create life-threatening blockages -- without you ever feeling a thing. Since we’re all at risk for coronary artery disease, it’s worth learning more about atherosclerosis.

  • About 18 million Americans ages 20 and older have heart disease.
  • More than 800,000 Americans have a heart attack each year. 
  • About 650,000 Americans die of heart disease every year.
  • About 25% of deaths in the U.S. is caused by coronary heart disease. 
  • Half of all men who have severe atherosclerosis with no symptoms.
  • More men than women die from coronary artery disease. The rates for women go up after menopause, but they never catch up with men's.
  • Heart disease is the No. 1 killer in women, just as in men.

Many of us have heard that clogged arteries lead to heart attacks. But how does atherosclerosis cause coronary artery disease?

First, the coronary arteries’ smooth interior surface is damaged. High blood pressure, abnormal cholesterol levels, cigarette smoking, and diabetes are the most common reasons why.

LDL -- or "bad" cholesterol -- then starts to build up in the coronary artery’s wall. The body sends a "clean-up crew" of white blood cells and other cells to the toxic site.

Over the course of years, continuing buildup of cholesterol and the body’s response to it create a plaque. That’s a bump on the artery wall that can obstruct blood flow.

Atherosclerosis plaques in the coronary arteries can behave in several ways:

They can grow slowly, never blocking the artery or causing clots.

They can expand and block blood flow in a coronary artery. This may cause no symptoms, even when the artery is very blocked.

Other times, a blockage does cause symptoms. Called “stable angina,” this is most commonly chest pain with activity. It goes away with rest. It’s not a heart attack, but it suggests you are at risk for one and should be treated aggressively with medications.

A plaque can rupture. That causes blood to clot quickly inside the coronary artery. A plaque rupture is as serious as it sounds. The result is a blood clot that makes your chest hurt.

Two things can happen then:

Unstable angina: The clot doesn't totally block the blood vessel. It then dissolves without causing a heart attack.

Heart attack (myocardial infarction): The coronary artery is blocked by the clot long enough to cause irreversible damage. The heart muscle, starved for nutrients and oxygen, dies.

Blood clots can form in any of the arteries of the heart, even those with only minor blockages.

No one can predict who will have a heart attack. But coronary artery disease isn’t random. Most people with coronary artery disease have one or more controllable risk factors.

Most people who have a heart attack will have at least one or more of the following risk factors that contribute to atherosclerosis and coronary artery disease:

Most of us have plenty of room for improvement.

The best way to determine your risk level is to see your doctor. But you can start to reduce your risk today. Eat right, don’t smoke, and exercise. Remember to check with your doctor before starting a new exercise plan.

Some people may also need to take medicine to keep their cholesterol and blood pressure in a healthy range.